Colorectal cancer is not currently on the list of diseases identified by the Surgeon General as being caused by cigarette smoking. Although the research literature has shown that cigarette smoking is associated with non-cancerous adenomenous polyps in the colon, the relationship to colorectal carcinoma is less definitive. Recent literature that includes studies with extended follow-up times reveal associations between smoking and colorectal cancer only after this long latent period; however, numerous other studies fail to find an association. The purpose of this study is to provide additional data to address the controversy in the literature about the relationship between cigarette smoking and colorectal cancer. Given that there are an estimated 135,400 new colorectal cancer cases each year and that colorectal cancer is very treatable when caught in an early stage, further knowledge about the etiologic role that cigarette smoking plays in the development of colorectal cancer may have population-wide implications for identifying persons at higher risk for disease who may be better candidates for colorectal cancer screening and for targeting smoking cessation services to high risk populations. This proposal outlines a plan for ascertaining the cancer incidence and mortality status of 9,343 (3,965 males and 5,738 females) persons who were seen at Roswell Park Cancer Institute between 1957 and 1965, who completed a detailed epidemiologic survey that included questions about their lifetime tobacco use and other lifestyle factors including their diet and their alcohol consumption, and who also received a non-cancer diagnosis. Cancer incidence and mortality status will be obtained by linkages with the New York State Cancer Registry, the New York State Vital Statistics Department, the Social Security Death Index, and the National Death Index. Hazard ratios for colorectal cancer incidence and mortality will be compared across varying levels of lifetime cigarette consumption to assess associations between cigarette consumption and colorectal cancer while controlling for potential confounders in multivariate Cox proportionate hazard model analyses. This dataset provides a unique resource to readily address this question since detailed epidemiologic data have already been collected on a large population and straightforward mechanisms exist to ascertain cancer and mortality status of this cohort. The primary hypothesis tested is that the risk for colorectal cancer incidence and mortality will be highest among persons with the largest lifetime consumption of cigarettes, particularly in those with more than 35 years of exposure, even after controlling for potential confounders.